{
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\begin{tabular}{l*{2}{c}}
\hline\hline
                    &\multicolumn{1}{c}{\specialcell{\;\;\;\;\; Arsenic \\ contamination \\ \;\;\;\;\;(WHO)}}&\multicolumn{1}{c}{\specialcell{\;\;\;\;\;\; Fecal \\ contamination}}\\\cmidrule(lr){2-2}\cmidrule(lr){3-3}
                    &\multicolumn{1}{c}{(1)}   &\multicolumn{1}{c}{(2)}   \\
\hline
Very poor x treated &      -0.097   &       0.018   \\
                    &     (0.066)   &     (0.091)   \\
Poor x treated      &      -0.042   &       0.069** \\
                    &     (0.034)   &     (0.029)   \\
Low income x treated&      -0.062** &      -0.028   \\
                    &     (0.030)   &     (0.031)   \\
Middle income x treated&      -0.055*  &      -0.069** \\
                    &     (0.031)   &     (0.028)   \\
High income x treated&       0.034   &      -0.057   \\
                    &     (0.077)   &     (0.123)   \\
\hline
R2                  &        0.08   &        0.05   \\
Obs                 &        6051   &        6051   \\
\hline\hline
\end{tabular}
}
